Patent GB-190510495-A (GB)
Title: Improvements in Methods of Charging and Discharging Electric Accumulators in Systems of Electric Distribution.
Inventor: ELLIS GEORGE SCOBELL
Filed: 1905-05-19
Granted: 1906-05-17
Abstract: 10,495. Ellis, G. S., and Taylor, A. M. May 19. Regulating.-In distributing; systems, involving the use of accumulators, the accumulators are given a daily charge which is automatically controlled to compensate for any previous discharge ; at the same time, means are provided for preventing the batteries from injury by excessive charge or discharge. The invention as illustrated is applied to systems such as that described in Specification No. 25,620, A.D. 1904, but it may also be applied to systems such as are described in Specification No. 1528, A.D. 1905. The motor b, fed from the mains h, i, through leads k, l, is coupled to the dynamo a, the brushes of which are connected to the secondary battery d ; a switch n opens and closes at certain times the circuit to a relay, such as is shown at s, governing the shunt regulating switch 3, and the main switch m. The direction of rotation of the relay motor s is determined by the direction in which the switch arm 9 moves, this depending upon which of the coils 10, 12 is energized. For instance, when the arm n makes contact with the plate p, the current from the battery t, (which may be part of the battery d), is closed through the coil 10, the lever 9 then rocking to the left and closing the circuit through the motor s, which turns the screw v and, raising the nut w, closes the switch m, putting the motor b on the mains and then gradually cutting out the resistance 3 in the field of the dynamo a, and, if desired, also cutting resistance into the field of the motor b. Further variations in the resistance of the field winding may be effected by the handswitch 49, and, while the dynamo a is charging the battery d, power for a printing-machine or the like may be taken from the pulley 84. When the arm n passes off the plate p, the circuits are broken, but, as it passes on to the plate q, they are again made, till, on leaving the plate q and going on to the plate r, the circuit is completed through the coil 12 ; the lever 9 then swings over to the right, and reverses the current from the battery t through the armature s, so as to make the nut w descend, put resistance in the dynamo field, and finally open the switch m. The dynamo now runs as a motor from the accumulators d, and the subsidiary lighting-circuit 50 may be supplied, on closing the switch 51, from the motor b running as a dynamo. If on account of fog &c. the switch 54 governing the lamps 53 is closed, the magnet 55 is energized, and opens the circuit of the charging-coil 10, and at the same time closes the circuit of the discharging-coil 12, so that during this time of abnormal demand the motor b is temoved from the mains and the dynamo is run as a motor from the cells d. The coils 10, 12 may be replaced by two small motors. The magnet 59 operates, when necessary, as a high and low voltage governor for the battery d, and the polarized relay 65 similarly governs the charging-current. If the electromotive force of the battery d becomes excessive, the magnet 69 opens the circuit of the charging coil 10. To ensure that the accumulator is given a charge corresponding to the amount previously taken out, a contact-arm 75 is attached to the slowly-moving axle 76 or dial of an ampere-hour meter, and two studs 78, 79 are arranged so as to operate relays which respectively stop and start charging the accumulators d. To compensate for loss due to running down in open circuit, a disk 84 of some good conductor is attached to the rapidly-moving axle 83 of the meter, and near this disk is placed a magnet 85 with a winding 88 thereon which is traversed by all or a proportion of the main battery current. During charging, this winding acts to strengthen the magnet, and by producing eddy currents in the disk retards the movement of the plate 84 ; during discharging, however, it tends to demagnetize the magnet, and by adjusting the rheostat 90 the difference in the time occupied by the arm 75 in moving from the stud 78 to the stud 79, from that required to make the movement in the opposite direction, can be made to compensate for internal losses. Instead of using one differentiallywound magnet, a separate magoet 100 may be used which is not energized during discharge.